Antibodies to Hu D antigen in serum, blot

Depending on the organ affected by the cancer, cancer cells express Ri, Yo, Hu antigens, which can induce the formation of specific autoantibodies. These autoantibodies bind to the corresponding antigens localized in nervous tissue and are thus implicated in neurological diseases known as paraneoplastic syndromes.

Paraneoplastic syndromes are defined as clinical syndromes accompanying cancerous tumors without regard to vascular or infectious factors or resulting from side effects of antitumor therapy. They are caused by immunological mechanisms triggered by the tumor, the effect of which can be manifested far from the site of the primary tumor and/or metastases.  Paraneoplastic syndromes accompany approximately 15% of cancers, especially lung cancer and gastric cancer.

Paraneoplastic-otoneuro-ophthalmologic syndromes commonly occur in brainstem encephalitis and/or cerebellar degeneration. The discoverable association of paraneoplastic syndromes with various immune responses to onconeuronal proteins or with immunologic mechanisms directed at unknown antigens is advancing research into these mechanisms.

Paraneoplastic syndrome or a positive test result for the presence of antibodies to the above antigens may warn of malignancy even before a diagnosis of cancer is made.

Patients who test positive for antineuronal antibodies should be immediately screened for tumors.

Determination of antibodies to Ri, Yo , Hu is essential for the diagnosis and monitoring of the course of the disease and the success of therapy in paraneoplastic neurologic syndromes (PNS), as they are associated with cancer. Antitumor therapy is also essential in the management of neurologic symptoms.

Determination of antibodies to Ri antigen is of diagnostic value in paraneoplastic syndromes (such as opsoclonus-myoclonus syndrome with ataxia, encephalitis of the rhomboid brain), rapidly growing brainstem tumors, small cell lung cancer, breast carcinoma, and ovarian carcinoma.

Determination of antibodies to Hu antigen is diagnostically important in paraneoplastic syndromes and in small cell lung cancer, prostate carcinoma and neuroblastoma.

However, in a small number of patients with paraneoplastic syndrome, malignancy is not detected in the presence of antineuronal antibodies. Some patients with paraneoplastic syndrome may not have detectable antineuronal antibodies. Antibodies

Typical associated tumors

Anti-Hu

ANNA-1

Sensory neuropathy

Chronic gastrointestinal pseudoobstruction

paraneoplastic cerebellar degeneration

limbic encephalitis

Small cell bronchial cancer

Аnti-Ri

ANNA2

Brainstem encephalitis.

Carcinoma of the breast

Small cell bronchial cancer